Method and system for external assessment of hearing aids that include implanted actuators

Abstract

A noninvasive method and system are provided for assessing the performance of implanted actuators of semi or fully-implantable hearing aid systems. The invention utilizes an externally positioned measurement device to obtain a test measure of the electrical signal passing through an implanted actuator when driven by a test signal of predetermined characteristics. In one embodiment, the measurement device may comprise a pair of coils for measuring the magnetic field generated by an implanted actuator utilized to simulate the middle ear of a patient. The magnetic field strength is directly related to the amount of current passing through the actuator. In turn, such current is inversely related to the electrical impedance present at the implanted actuator. Such electrical impedance is directly related to the mechanical impedance present at the interface between the implanted actuator and middle ear of a patient. As such, by driving an implanted actuator at one or more predetermined frequencies the resultant magnetic field measures may be utilized to assess whether the implanted actuator is operative and whether a desired interface between the actuator and the middle ear of patient (e.g. the ossicular chain) is present.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority as a divisional application to U.S. patent application Ser. No. 10 / 082,989 filed on Feb. 26, 2002, entitled “METHOD AND SYSTEM FOR EXTERNAL ASSESSMENT OF HEARING AIDS THAT INCLUDE IMPLANTED ACTUATORS”. The foregoing application is incorporated herein by reference in its entirety.FIELD OF THE INVENTION [0002] The present invention relates to the field of hearing aid devices that include implanted actuators, and more particularly, to assessment of the performance of hearing aids using a magnetic field generated in response to an electrical signal passing through the actuator. BACKGROUND OF THE INVENTION [0003] Implantable hearing aid systems entail the subcutaneous positioning of various componentry on or within a patient's skull, typically at locations proximal to the mastoid process. In semi-implantable systems, a microphone, signal processor, and transmitter may be externally located to receive, process...

AI Technical Summary

Benefits of technology

The present invention provides a method and system for non-invasive assessment of the performance of implanted hearing aid actuators and interconnected componentry. The method involves positioning a test device external to a patient and using it to obtain test measures indicative of an electrical signal passing through the implanted actuator. These measures are then used to assess the performance of the actuator and the interface between it and the patient's middle ear. The method is simple and straightforward, and can be easily incorporated into a routine office visit evaluation. The invention also provides a way to non-invasively adjust the position of the actuator to achieve a desirable interface with the patient's middle ear. The technical effects of the invention include improved non-invasive assessment of implanted hearing aid actuators and interconnected componentry, as well as a simplified and straightforward method for evaluating the performance of these devices.

Problems solved by technology

Overloading or biasing of the attachment can result in damage or degraded performance of the biological aspect (movement of the ossicular chain) as well as degraded performance of the mechanical aspect (movement of the vibratory member).

Unfortunately, however, these devices suffer from several drawbacks.

One drawback is that finite movements of the actuator are limited by the thread size of the screw.

While it is often desirable to achieve a more finite adjustment of the actuator position, it is often not possible because of limitations in the available thread sizes.

Another drawback is that regardless of tolerances in the system and screw design, a certain amount of “backlash” (movement of the screw in the reverse direction when forward pressure from the adjustment tool is released) exists in the system.

In some cases, several attempts at achieving the interface position must be made because of the unpredictability of the “backlash” in the system.

Also unfortunately, patients may experience a “drop-off” in hearing function after implantation due to changes in the physical engagement of the actuator caused by tissue growth.

After implantation, however, it is difficult to readily assess the performance and adjust an implanted hearing aid actuator and interconnected componentry.

For example, it is difficult to assess whether the vibratory member is in the desired physical engagement with the ossicular chain.

Further, in the event of a “drop-off” in hearing after implantation, it is difficult to determine the cause, e.g. over / under loading of the interface or some other problem with the hearing aid, without invasive and potentially unnecessary surgery.

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